High pressure high temperature punch member



June 29, 1965 WENTQRF, JR 3,191,231

HIGH PRESSURE HIGH TEMPERATURE PUNCH MEMBER Filed March 26, 1963 [r7 ve7'? to r-: Robert H WentorFJr-j aflM miizme United States Patent3,191,231 HIGH PRESSURE HIGH TEMPERATURE PUNCH MEMBER Robert H. Wentorf,Jr., Schenectady, N.Y., assignor to General Electric Company, acorporation of New York Filed Mar. 26, 1963, Ser. No. 268,096 2 Claims.(CI. 1816) This invention relates to a high pressure, high temperatureapparatus punch member and more particularly to such a punch memberhaving a very hard material nib projection on the working end or facethereof. In general, high pressure high temperature apparatuses utilizea plurality of pressure resisting members, one or more of which movetowards another to define a reaction chamber in which a specimenmaterial is placed to be subjected to high pressures and hightemperatures. The ends of these pressure resisting members are subjectedto extreme temperatures and pressures and thus to critical stresseswhich cause many failures to occur at the very ends of the punchmembers. These failures usuually encompass only a very small portion ofthe end area and volume. Such a small failure yet results in thenecessity of replacing the entire punch assembly which is usually of avery high strength, high cost, and difficultto-work material.

Accordingly, it is an object of this invention to provide an improvedpunch member.

It is another object of this invention to provide a high pressure hightemperature punch member with a separable end portion.

- It is another object of this invention to provide a nib projection onthe tip of a high pressure high temperature punch member.

It is another object of this invention to provide a refractory nibprojection on the end of a high pressure high temperature punch member.

Briefly described this invention includes a refractory nib projection onthe end of a tapered, hard metal punch member, which follows the generalcontour of the tapered punch member and extends the punch face to a newface on the nib projection which is of smaller cross sectional area thanthe face of the hard metal punch member.

This invention will be better understood when taken in connection withthe following description and the drawing in which:

FIG. 1 is an illustration of the nib member of this invention as appliedto a punch member having tapered and arcuate surfaces;

FIG. 2 is an illustration of a nib member according to the practices ofthis invention when applied to a punch member of generally angular crosssection; and

FIG. 3 is an illustration of one use of nib members between a pluralityof lateral punches.

Two general types of high pressure high temperature apparatuses to whichthis invention is particularly applicable are disclosed in US Patents2,941,248Ha1l and 3,107,395-Bundy, assigned to the same assignee as thepresent invention. The belt apparatus disclosed in the aforementionedHall patent, comprises in one embodiment, a pair of oppositelypositioned frustoconical punch members which move into a convergentdivergent opening in an intermediate concentrically positioned die orbelt member. A specimen material in the die member and between thepunches is compressed by motion of the punches towards each other.

The apparatus disclosed in the aforementioned Bundy patent comprises areaction chamber defined by the smaller end faces of a plurality oftrapezoidal punch members, for example six, all of which move towards adefined center and interfit with each other to define a 3,191,231Patented June 29, 1965 Led reaction chamber. A specimen material isplaced in the reaction vessel to be subjected to high pressures and hightemperatures. A ceramic or stone material gasket is employed in theseapparatuses between all punches, where applicable, and between thepunches and the belt or die in the belt apparatus.

In either of the above described apparatus, the punch faces, i.e., theinner faces which define the walls of the reaction vessel, are subjectedto the highest pressures, the highest temperatures, and the highestcritical stresses. It is thus an important practice that thermalinsulation, in the form of ceramic or stone gasketing, be employedbetween the punch face and the center of the reaction vessel in order toshield the punch face from the high temperatures in the reaction vessel.It is also an important feature and a matter of standard practice toenclose the side surfaces of the punch members with ceramic or stonegasket materials to adequately support the punch face. In most instancesthis practice is included in the use of gasketing between punches orbetween punches and confining members.

Under the conditions of high pressures and high temperatures, even suchmaterials as the cemented tungsten carbides become somewhat plastic andare subject to failure. These failures are usually evidenced by cracksin the punch face or by small sections of the punch face breaking off.One cause of such failures is loss of lateral support at the punch facewhich exerts extraordinarily high forces on the punch causing a materialflow and failure. A primary contributing factor to these failures is theexposure of the punches to the very high temperatures in the samplewhich substantially weakens the punch material. Severe limitations areimposed on the distance from the punch to the specimen because, forexample, added materials diminish pressure generation ability of theapparatus or contribute prohibitive gasketing problems.

It has been discovered that a small nib of a refractory material, forexample alumina, cubic boron nitride, beryllia, or zirconia may beattached to the punch faces and positioned between the punch faces andthe specimen or the reaction vessel. The nib is more resistant to hightemperatures while at the same time replaces gasket or reaction vesselmaterial to provide higher pressures with less stroke or punch travel.However, where very high temperatures are not a problem or are notutilized, the nib of this invention may be metallic. In any event theuse of nibs precludes the necessity of replacing the entire punch memberin those very high pressure high temperature operations where punchbreakage is common. Cermet materials may also be utilized for thesenibs.

On particular example of the practice of this invention is illustratedin FIG. 1. Referring now to FIG. 1, there is illustrated a punch member10 such as shown in the aforementioned Hall patent. Punch member 10comprises a cylindrical base structure 11 and a tapered or frustoconicalportion 12 extending from the base 11. Nib 13, in accordance with thepractice of this invention, is placed on the face 14 of punch 10. Thisnib portion 13 includes a side surface 15 which is smoothly integratedwith the contour of punch portion 12. Surface 15 follows the sameprojecting pattern of punch portion 12 to provide a face portion 16which is smaller than face portion 14- of punch portion 12. For example,a frustoconical punch includes, preferably, a frustoconical nib wherethe nib is a graphical projection of the frustoconical configuration ofthe punch. The side surface of the nib may, however, be a smooth curvetangentially engaging the outline curve of the tapered surface of thepunch.

The longitudinal extension of the thickness .of such a nib 13 isrestricted to be as small as possible commen- 3 surate with the axialdimension of ordinary tip failures of the punches. The thickness must bemaintained of a minimal dimension because the refractory material needsmore support by way of gasket materials to maintain a structuralintegrity thanldo the hard steels and cemented carbidesof' which thepunch members are usually rnade. Accordingly the nib projection must becon- 7(4) The nib material receives the brunt of thesevere tinuallysupported over its entire thickness. In a belt type apparatus, theeffective gasketing between the punch and die member must. extend alongthe punch and die members a distance greater'than the extension orthickness of the nib. The same practice is true of interfitting punchassemblies where the gasket therebetween must be axially longer than thethickness of the nib.

In FIG. 2, there is shown a prism or trapezoidal punch 20 wherein asmall nib 2:1 is positioned on the face 22 of punch 20 as anextension'thereof. Nib 21 defines a face portion 23 smaller than faceportion 22 of punch 20. The purposes for which nib 21 is employed arethe same as those described for'FIG. 1.

FlG. 3 illustrates four punches 24,25, 26, and 27 (each similar to punch20 of FIG. 2), circumferentially arranged .to define a reaction chamberor zone 28.. In

(3) For a given reaction zone pressure, the total length of the gasketis increased over that ordinarily used. Thus, the average pressure onthe gradient in the gasket is reduced and the local stresses on thepunches are also reduced.

. stress and thermal-gradients. However, they are small, I economical,and easily replaced.

In the practices of this invention, the nibs are usually employed'bybeing fastened to the corresponding faces of the punches. Suchfastening, however, should not take the form of any opening in the nibor in the punch such as for bolts, attac'hing flanges, etc. The use ofthe nibs in this invention has'been limited to semipermanent attachingmeans in the form of various glues and cements, such as rubber glues,epoxy resin, etc., which do not impose any undue stress concentrationson either the nib or the punch through any materi'alremoval.

a 6-punch assembly, as disclosed in the aforementioned:

gaskets may terminate at the end of the nib, or, as illustrated, mayextend furthertowards the reaction zone to define the walls of the zone.In the latter instance, further thermal insulators 37, 38, 39, and 40are employed at the ends of the nibs as filler elements. i

- Particular advantages of the. use of sucha nib in the practice of thisinvention are:

(1) Relatively compressible insulating. stone materialis replaced byrather incompressible nib material so that the punches need nottravellas far to producehighi pressure in the reaction zone, and thusthe demands upon the ga'sketing material are less severe. (2) The nibsaid in concentrating the force from the punchface to the reaction zone,after the manner of a tapered punch so that the pressure is'higher atthe 7 nib face in the reaction zone than on the punch face. Because thenibs are exposed to high pressure on all sides, their strength andductility, insofar as their refractory material is concerned, areimproved, and relatively brittle but high strength refractory materialscan be used' for the nibs..

Whilev a specific method and apparatus in accordance with this inventionis described and shown, it is not intended that the invention be limitedto theparticular description nor to v the' particular configurationsillustrated, and it is intended by theappended claims to cover allmodifications within the spirit and scope of this.

invention. i a

What I claim as new and desire to secure by Letters Patent of theUnitedStates is: v

,1. 'In a high'pressure apparatus wherein a plurality of punches arearranged in opposed relationship with suitable gasket materialcontiguous with each punch Wherebymovement of'atleast one punch causescompression of the gasket material andtransmits high pressure toa closedreaction vessel, the improvement comprising:

' (a) a nib positioned on and extendingfrom the distal end-.of eachofsaid'punches inwardly toward the IClOSGd reaction chamber, I

' (1) each of said ni'b's'being harder than the-ina- V terial,comprisingsaidpunches'and thebase area of each -n ib;being sim ilar to andinmating relationship with the face offthe distal end of its respectivepun-chf j j 2. The improvement substantially as recited in claim whereineach nib is composed of refract'ory' material.

" 3,096,862 -6/6 3 Gerard et al.

3,096,544 7/63 Lundblad. 7. 3,118,177 1/64 Von Platen 18-5 WILLIAMl I.STEPHENSON, Primar Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,191,231 June 29, 1965 Robert H. Wentorf, Jr.

It is hereby certified that error appears in the above numbered patentrequiring correction and that the said Letters Patent should read ascorrected below.

Column 4, line 39, strike out "and the" and insert instead each nibtapering from a line 40, strike out "of each nib being"; line 42, after"punch" insert to a terminal face having an area smaller than said basearea Signed and sealed this 21st day of December 1965.

(SEAL) Attest:

ERNEST W. SW'IDER EDWARD J. BRENNER Attesting Officer Commissioner ofPatents

1. IN A HIGH PRESSURE APPARATUS WHEREIN A PLURALITY OF PUNCHES ARE ARRANGED IN OPPOSED RELATIONSHIP WITH SUITABLE GASKET MATERIAL CONTIGUOUS WITH EACH PUNCH WHEREBY MOVEMENT OF AT LEAST ONE PUNCH CAUSES COMPRESSION OF THE GASKET MATERIAL AND TRANSMITS HIGH PRESSURE TO A CLOSED REACTION VESSEL, THE IMPROVEMENT COMPRISING: (A) A NIB POSITIONED ON AND EXTENDING FROM THE DISTAL END OF EACH OF SAID PUNCHES INWARDLY TOWARD THE CLOSED REACTION CHAMBER, (1) EACH OF SAID NIBS BEING HARDER THAN THE MATERIAL COMPRISING SAID PUNCHES AND THE BASE AREA OF EACH NIB BEING SIMILAR TO AND IN MATING RELATIONSHIP WITH THE FACE OF THE DISTAL END OF ITS RESPECTIVE PUNCH. 